The invention relates to vapor analysis.
Vapor analysis is used by industrial hygienists and others to monitor the concentration of contaminants in the air. In a typical application, a vapor analyzer draws in a sample of contaminated air through a sample probe, analyzes the air sample, and displays the concentration of contaminants in parts-per-million ("PPM").
Flame-ionization detection measures the concentration of most organic contaminants in an air sample by ionizing organic contaminants, such as hydrocarbons, contained in the air sample in a hydrogen flame. The hydrogen flame heats the air sample and produces ions in proportion to the concentration of contaminants in the air sample. Detection circuitry counts these ions and, based on the count, produces a measurement of the concentration of contaminants in the air sample.
Photo-ionization detection, a technique that measures the concentration of many organic contaminants and some inorganic contaminants, produces ions by subjecting the air sample to ultraviolet energy. The ions are detected, and a measurement is produced, in a manner similar to that used in flame-ionization detection.